Supersonic aircraft



FIG. 1 is a front and side perspective view of a subsonic aircraft showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a top plan view thereof; and

FIG. 5 is a side elevational view thereof, the opposite side elevational view being a mirror image of that shown. 

The ornamental design for a supersonic aircraft, as shown and described. 